Polyimide copolymers and method for fabricating patterned metal oxide layers

Abstract

A polyimide copolymer represented by formula (I) or formula (II) is provided. In formula (I) or formula (II), B is a cycloaliphatic group or aromatic group, A is an aromatic group, R is hydrogen or phenyl, and m and n are 20-50. The invention also provides a method for fabricating a patterned metal oxide layer.

What is claimed is: 
     
       1. A polyimide copolymer represented by formula (I) or formula (II): 
       
         
           
           
               
               
           
         
         wherein 
         when A is 
       
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         R is hydrogen or phenyl; and 
         m and n are 20-50. 
       
     
     
       2. The polyimide copolymer as claimed in  claim 1 , wherein the polyimide copolymer has an aniline terminal. 
     
     
       3. The polyimide copolymer as claimed in  claim 1 , wherein the polyimide copolymer has a weight-average molecular weight of about 6,000-15,000. 
     
     
       4. The polyimide copolymer as claimed in  claim 1 , wherein the polyimide copolymer has a weight-average molecular weight of about 6,000-12,000. 
     
     
       5. A method for preparing a polyimide copolymer, comprising:
 mixing a diamine (A) and a dianhydride (B) together to form a polyimide precursor, wherein when A is 
 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         mixing an aniline and the polyimide precursor together to form a reaction mixture; and 
         imidizing the reaction mixture to prepare a polyimide copolymer. 
       
     
     
       6. The method for preparing the polyimide copolymer as claimed in  claim 5 , wherein the aniline has a molar ratio of about 10-20% in the reaction mixture. 
     
     
       7. The method for preparing the polyimide copolymer as claimed in  claim 5 , wherein the aniline has a molar ratio of about 15-20% in the reaction mixture. 
     
     
       8. A method for fabricating a patterned metal oxide layer, comprising the following steps:
 providing a substrate; 
 forming a patterned polyimide layer on the substrate, wherein the polyimide layer is prepared by the method for preparing the polyimide copolymer as claimed in  claim 5 ; 
 forming a metal oxide layer on the substrate and the patterned polyimide layer; and 
 removing the patterned polyimide layer to form a patterned metal oxide layer. 
 
     
     
       9. The method for fabricating a patterned metal oxide layer as claimed in  claim 8 , wherein the aniline has a molar ratio of about 10-20% in the reaction mixture in the method for preparing the polyimide copolymer. 
     
     
       10. The method for fabricating a patterned metal oxide layer as claimed in  claim 8 , wherein the substrate comprises silicon, glass or ceramic. 
     
     
       11. The method for fabricating a patterned metal oxide layer as claimed in  claim 8 , wherein the patterned polyimide layer is formed on the substrate by a printing process. 
     
     
       12. The method for fabricating a patterned metal oxide layer as claimed in  claim 8 , wherein the metal oxide layer comprises fluorine-doped tin oxide (FTO), aluminum oxide or indium tin oxide (ITO). 
     
     
       13. The method for fabricating a patterned metal oxide layer as claimed in  claim 8 , wherein the metal oxide layer is formed on the substrate and the patterned polyimide layer by a deposition process. 
     
     
       14. The method for fabricating a patterned metal oxide layer as claimed in  claim 8 , wherein the patterned polyimide layer is removed by placing the substrate in an organic solvent. 
     
     
       15. The method for fabricating a patterned metal oxide layer as claimed in  claim 14 , wherein the organic solvent comprises N-methyl-2-pyrrolidone (NMP), N,N-dimethyl formamide (DMF), γ-butyrolactone (GBL), dimethyl sulfoxide (DMSO), ethanolamine, catechol or a combination thereof. 
     
     
       16. The method for fabricating a patterned metal oxide layer as claimed in  claim 8 , further comprising hard-baking the patterned polyimide layer before the metal oxide layer is formed on the substrate and the patterned polyimide layer.